1. Field of the Invention
This invention relates generally to communicating information encoded in a bar code format, and more specifically to systems, methods and apparatus for communicating information encoded in a bar code format from a mobile digital device to a bar code scanner.
2. Description of the Related Art
The use of bar code scanners in a great many aspects of everyday life is commonplace. Bar code scanners are found in many different types of facilities, including supermarkets, airport security, check-in and boarding areas, stadiums, libraries, test centers, conference centers, and many other places. The use of bar code scanners has dramatically increased the speed at which many commonplace transactions can be completed.
While typically printed on paper labels and stubs, bar codes may also be shown on display screens; for example, in International Publication no. WO 00/03328 dated Jan. 20, 2000, Motorola Inc. of Schaumburg, Ill., describes the display of bar coded information on a selective call receiver (“SCR”). Demographic information concerning the user of the SCR is stored in the SCR. The demographic information is visually displayed on the SCR as a bar code such that it can be read by a bar code scanner, as in a store or at a point-of-sale. A stored coupon may also be displayed in bar code format so that it can be read and redeemed at the point-of-sale. A stored affinity card code and a unique identifier may also be displayed in bar code format so that they can be read to identify a selected affinity group and the customer at the point-of-sale. As a further example, Aeritas Inc. of Dallas, Tex., has proposed using voice recognition technology to allow a cellular telephone user to identify himself or herself while obtaining wirelessly from an airline computer an electronic bar coded boarding pass at the airport using only a cellular telephone. As proposed, the electronic boarding pass may be displayed as a bar code at the time of boarding on the screen of the cellular telephone so that the gate attendant may scan the boarding pass in a conventional manner.
While presenting information such as coupons and user affinity information in bar code form on a cell phone display can be quite useful, the technique has several disadvantages. Some bar code scanners, for example, cannot reliably read bar codes displayed on certain types of cellular phone displays because the contrast ratio between the bars and spaces shown on the screen, which typically is a liquid crystal display (“LCD”), is not sufficient. Further, the physical dimension and/or resolution of the display may also limit the size of the bar code that may be displayed at one time.
U.S. Pat. No. 6,685,093 issued Feb. 3, 2004 to Challa et al. describes a variety of techniques for communicating information between a mobile communications device and a bar code reader. U.S. Pat. No. 6,877,665 issued Apr. 12, 2005 to Challa et al. describes a variety of techniques for communicating information encoded in a light-based signal using a fob device. While the techniques described in these Challa et al. patent are extremely useful across a broad range of applications, further improvement is desired.